SPGBIO: LESSON 3

• Types of vessels involved in plant transport


  • Xylem
  • Phloem
• Xylem vessels


  Transport water around the plant; this transport is called "transpiration"
• Phloem vessels


  Transport nutrients (source to sink); this transport is called "translocation"
• XYLEM: Transpiration - the loss of water vapour from the stems and leaves (it is an inevitable consequence of gace exchange)

  transpiration involves the following stages:

  1. water vapor is lost from leaves via evaporation
  2. new water is absorbed from the soil by the roots
  3. this creates a pressure difference in leaves and roots
  4. water will flow up the stem (in xylem) via mass flow

  PHLOEM: Translocation
• Transpiration

  1. Water vapor is lost from leaves via evaporation

  2. New water is absorbed from the soil by the roots

  3. This creates a pressure difference in leaves and roots

  4. Water will flow up the stem (in xylem) via mass flow
• Transpiration

  The loss of water vapour from the stems and leaves (it is an inevitable consequence of gace exchange)
• Translocation

  1. Organic molecules are transported via a tube system called phloem, via the process of active translocation

  2. Active loading of solutes into the phloem draws water from the xylem, creating a pressure gradient (mass flow)
• Translocation

  Plants transport organic molecule from sources to sinks
• Sources

  • Photosynthetic tissues (e.g. leaves)
• Sinks


  • Storage organs (e.g. fruits, seeds, roots)
• Animals are made of trillions of cells, and each cell in the body needs a supply of oxygen and nutrients in order to survive
• Circulatory system


  All animals need a special delivery system to deliver these nutrients and take away wastes
• Types of Circulatory System

  • Open Tape (found in arthropods and mollusks)
  • Close Tape (the blood is enclosed in a highway of vessels)
• Hemocoel


  Open means there is no vessels, so all body goo is just floating around free in the animal's body cavity
• Evolution of Circulatory System

  • Fish - 2 chamber
  • Amphibian - 3 chamber
  • Reptiles - 3 chamber
  • Birds & Mammals - 4 chamber
• Heart

  • Four-chambered hollow muscle
  • Top Chamber (atria) - used as reservoirs
  • Bottom Chamber (ventricles) - are pumps
• Cardio-pulmonary Circulation

  1. Left side is involved in systemic circulation (moves oxygenated blood from lungs to body)

  2. Right side is used for pulmonary circulation (moves deoxygenated blood from body to lungs)
• Heart structure

  • Contains four chambers: two atria (reservoirs) and two ventricles (pumps)
  • Every chamber possess a heart valve to prevent the backflow of blood
  • Chambers are connected to blood vessels (veins - atria ; ventricles - arteries)
• Blood Vessels

  • Arteries - transport blood from the heart at high pressure (have thick walls)
  • Capillaries - exchange material between blood and tissue (single endothelial layer)
  • Veins - transport blood black to the heart at low pressure (have thin walls)
• Vascular System

  A closed network – the vessels are all connected
• Vascular System

  1. Arteries branch into smaller diameter arterioles, which diverge into capillaries

  2. Veins are formed from converging venules, pooling the blood from capillaries
• ARTERY

  • Function: sends blood from heart
  • Pressure: High (80-120 mmHg)
  • Diameter: Narrow
  • Wall: Thick
• CAPILLARY

  • Function: material exchange
  • Pressure: Low (<15 mmHg)
  • Diameter: Wide
  • Wall: Very thin
• VEIN

  • Function: sends blood to heart
  • Pressure: Low (5-10 mmHg)
  • Diameter: Extremely narrow
  • Wall: Thin
• BLOOD

  Fluid medium in which materials are transported around the body via blood vessels
• Liquid Plasma

  Responsible for transporting dissolved materials, electrolytes and proteins
• Plasma contains three types of blood cells

  • Red blood cells - transport oxygen (erythrocytes)
  • White blood cells - fight infections (leukocytes)
  • Platelets - involved in clotting (thrombocytes)
• Plasma Components

  • Nutrients (glucose, amino acids)
  • Antibodies (immunoglobulins)
  • Carbon dioxide (respiratory waste)
  • Hormones (chemical messengers)
  • Oxygen (respiratory requirement)
  • Urae (nitrogenous waste products)
  • Heat (important for thermoregulation)